Watchcase construction



June 25, 1940. L HQFFER 2,205,407

WATCHCASE CONSTRUCTION Filed July 16, 1936 INVENTOR.

% 2M3, ATTORNEYS Patented June 25, 1940 UNITED STATES PATENT orr caws'rcnoasnoonsmuc'non Leopold Hofier, Cincinnati, Ohio Application July16,1936, SBHBIINO. 90,941

6 Claims. (01. 58-90) My invention relates to watchcases and moreespecially to watchcases of the simpler and smaller types, notably wristwatches, in which, as heretofore manufactured, the support for thewinding and setting stem of the watch movement, in the watch case, hasbeen inadequately provided for, and in which usually the closuretherearound has been insufiiciently provided against entrance of foreignmatter to the watch movement.

The type of watchcases to which my invention is more especially directedusually are simply drawn up and formed of sheet metal, and for admittingthe movement stem there is left simply an opening amply large withoutany attention to forming this opening in such a manner as to accuratelyreceive the stem whereby it could afford an adequate bearing and anadequate closure around the stem. In many instances the shape of thisopening is merely that which results from forming an opening in theblank and allowing this opening to change its form incident to theforming operation on the blank, so that the opening is very irregular inshape and must be provided so as to be amply larger than the stem onaccount of this irregularity of shape.

In instances where the opening receives the stem closely the extent ofthe bearing may be only that of the thickness of the sheet metal, whichbecomes worn away so that there is no longer a bearing or support forthe stern, nor sufiicient closure to exclude foreign substances from thecase.

In any of these situations, with the stem not having a bearing in thewatchcase in addition to its bearing in the watch movement, of which itforms part, the stem, in its extension from the watch movement outthrough the case, is liable to considerable deflection under thepressure of winding operation, so that not only does the watch seem tobe fl msily constructed, but there is actually an undesirable tendencyfor the stem to wear in its hearings in the watch movement,

and the lack of the support of the stem increases the possibility ofbending and breaking the stem.

To leave a considerable opening for the entrance of dirt, dust, andmoisture, including perspiration of the wearer, of course greatlyincreases the depreciation of the watch movement from clogging,excessive wear, rust and corrosion of the movement parts, in addition tothe damaging tendencies due to the lack of proper support of the stemabove pointed out.

Furthermore in a large proportion of watch- I cases of the type withwhich my invention is especially concerned, not only is the stem notproperly supported but the crown is spaced out away from the exterior ofthe watchcase, either very noticeably, or at least to that extent thatis necessary on account of there having been no attention given toforming the exterior of the case to an accurate bearing of the crownagainst it. The result of this is that the crown, as regards to itsconnection to the stem, is subject to considerable tilting strain in theoperation of 10 winding and therefore is liable to be bent out of properposition on the stem, or may even be, in time, broken from the stem.

It is the object of my invention to provide against the above defectsfound with the usual 5 watchcases, so as to provide the stem with anadequate bearing, to provide adequate closure around the stem, and alsopreferably to adequately support the crown, so that the stem and crownwill be supported against the strains of winding operations and so thatdurable bearing will be afforded in the watchcase for the stem.

My improved construction, though not limited thereto, is especiallyadapted for provision, by watch repairmen, in cases already constructed,of a support member which is made especially to fit the particularwatchcase, in the manner hereinafter to be described.

Further objects will appear in the course of the following description,illustrated by the accompanying drawing, in which Fig. 1 is a frontelevation of a three-piece wrist watchcase to which my invention isapplied;

Fig. 2 is an enlarged edge elevation of the same, partly in section onthe line 2-2 of Fig. 1;

r Fig. 3 is a detail perspective view of the support member involved inmy improved construcron; v v V Fig. 4 is aperspective view of athree-piece watchcase of modified shape but of thesame con- 40 structionas that of Figs. 1 and2- so far as my invention: is concerned, thesupport member being shown above the watchcase, and the watchcase beingonly partially assembled or closed; and I Fig. 5, in a similar manner,illustrates a similar watchcasabut of two-piece construction, il,lustrating how my invention is embodied therein.

. H or H and the bezel 12 or [2' carrying the crystal 13 or 13.

As is well known in the art, such a watchcase as illustrated isconstructed for that mode of assembly. It will be under- 55 stood,however, that these details, and any other details of assembly ofwatchcaseipieces, or of their shape, do not materially afiect myinvention.

The part of the case with which my invention is intimately concerned isthe stem opening It in the center Iii or Id.

In Fig. 2 a watch movement I5 is shown mounted in the center iii bymeans of case screws it in the usual manner. The winding and settingstem. ill, usually considered as part of the movement it, is received inand supported by the movement I5, but it is understood, as ordinarilyprovided, would be readily detachable from the movement in the course ofinserting or removing the movement into or from the watchcase.

As previously explained, the opening it is not usually accurately formedin the relatively thin Walls of the case center it or Iii and is formedsufficiently larger than the stem to avoid necessity of accuratelyforming this opening. In i1- lustrating, I have not shown the watchcasewith this usual irregular opening but show it with an accurate circularopening aligned with the stem bearing in the movement it, the openingbeing relatively much larger than the diameter of the stem portion thatpasses through the opening; this size and accuracy having been providedas a part of the operation of embodying my invention in the watchcase ofthe usual less accurate construction.

Into this opening is accurately fitted the stem and crown support memberI8, which comprises a main hollow, cylindrical body portion having, atone end only, a relatively widely projected annular flange I9. Theexterior of the body portion accurately fills the opening I 4, theflange I9 closely abutting the exterior of the watchcase center ill or I0 around the openin I4; and the cylindrical interior 20 forms thebearing for the stem while the top or outer surface of the support I8forms a bearing for the under surface of the crown 2|, preferablybeingof such diameter as to receive the greater part of the area of thisunder surface; This support member I8 fits the opening Ilsuflicientlytight to remain stationary in the center II] or III", and although theexterior surface 22 of the center III or I0 has only such accuracy as isgiven in forming this center by the usual methods of large quantityproduction, it will be understood that the flange I9 will fitsufilciently accurately to give the support member I8 a firm bearing, sothat it maintains an accurate relation to the movement I5 and the stemI! thereof.

The flange III also adds to the distance that must be traveled byforeign substances to enter the case, thus adding to the effectivenessof the closure formed around the stem.

Many of the watch movements have the stem ll of the constructionillustrated in Fig. 2 in which thereis an enlargement or hub 23 unitarywith the stem I'I immediately under the crown 2| and extending aconsiderable distance therefrom-along the stem. This enlargement or hubserves in the ordinary construction to reinforce the connection of thestem and its crown.

In addition to the movements incident to winding, it is of courseunderstood that there is also an axial movement of the stem to bring itinto and out of position for setting the watch, and although this doesnot occasion nearly as much wear, it does create a condition in whichlack of support leaves the stem and crown greatly exposed to the dangersof bending and breaking.

With regard to the wear in the bearing, if the usual watchcase only isallowed to form the bearing for the stem, it will be understood that thewatchcase part is not only usually. too thin to form an adequate bearingas above noted but is usually made of a relatively soft metal such asgo1d,.silver, platinum or the like, not adapted to form a suitablebearing, whatever its extent may happen to be. Also it should be wellunderstood that in a great many watchcases the opening I4 is not formedfor the stem to fit it at all but is left in the case as formed, in themanner previously pointed out. It is of course desirable that thesupport member I8 should be of material hard enough to add to the lifeof the bearing over that permitted by the ample area of the bearing; andit is also desirable that the member should be of material that willwell resist corrosion. Accordingly, though ordinary 'steel affords thehardest bearings, it is more desirable to use a rustproof material, suchas brass, bronze, German silver or any one of a large number ofcorrosion resisting alloys known in the art. Stainless steel may beused. It will be understood of course that I am not limited as to themates rial used in the member I8.

In the cases of two-piec construction, as shown in Fig. 5, the back Ilareceives the bezel or front I20; in telescoping relation; the back i inbeing formed with a shoulder 22a, all around, of the thickness of themetal of the bezel I2a. These cases usually are made with two parts Ilaand I2a having notches Ma and Nb respectively which register to leave anopening for the movement stem when the case has been assembled. However,in the usual quantity production, when the case parts Na and I 2a areformed of sheet metal, these notches are allowed to have merely theirregular shape incident to drawing up the material after the notcheshave been formed in the blanks, with the notches amply large to avoidaccurate fitting around the stem.

With watchcases of this construction, my invention is incorporated bybringing the back Ila and bezel I2a into assembled relation, and thenaccurately enlarging the opening formed by the notches Ila and Nb inaccurate alignment with the bearing in the watch movement in the samemanner as the opening in the center of the threepiece case is treated,according to the previous description. Then the support memben I8 isformed to accurately fit the opening thus provided, with its flange I9fitting against the edge surfaces of the case'portions Ho and Ho aspermitted by the shoulders 22a which brings these surfaces substantiallyin a single plane.

I have shown modifications in which my invention is embodied, but itwill be understood that other modifications will'arise, and what I claimis:

1. In a watchcase construction, in combination with a watchcase havingan opening through which extends the stem of a watch movement mounted inthe case, said opening being of greater diameter than the part of thestem therein, a support and sealing member comprising a cylindrical bodyportion extending through and frictionally held in said opening, with acentral axial passage around which its walls are continuous from end toend, forming a bearing for the stem interiorly and a sealing contactwith the case-opening edge exteriorly; said member also comprising aflange at the outer end of the sup 'port member having a bearing againstthe exterior surface of the case around said opening,

the opposite end of said body portion being devoid of flange or otherextension, permitting said support member to be inserted from theexterior of the case into said opening, said opening having suchaccurate concentricity with the stem that said support member, held insaid opening due only to its frictional contact therein and said bearingof said flange against the case, operatively supports the stem and sealsthe watchcase therearound, for the purposes set forth.

2. A watchcase construction as set forth in claim 1, in which the flangeis so proportioned that, when bearing against the case as therein setforth, it also has a bearing and supporting contact with the crown ofthe stem when the stem is in operative position in the support memberand watch movement and is adjusted to movement winding position.

3. A watchcase construction as set forth in claim 1, in which the stemhas a crown and has a hub or neck portion reinforcing the connection ofthe stem and its crown, of materially greater diameter than themovement-engaging part of the stem and operatively received in theinterior passage of the support member.

4. A watchcase construction as set forth in claim 1, in which the stemhas a crown and has a hub or neck portion reinforcing the connection ofthe stem and its crown, of materially greater diameter than themovement-engaging part of the stem and operatively received in theinterior passage of the support member, and in which the flange of thesupport member is so proportioned that, when bearing against the case astherein set forth, it also has a bearing and supporting contact with thecrown of the stem when the stem is in operative position in the supportmember and the watch movement and is adjusted to movement windingposition.

5. A watchcase construction as set forth in claim 1, in which the casepart having the opening is the center member of the case and containsthe opening completely within its structure.

6. A watchcase construction as set forth in claim 1, in which thewatchcase comprises telescoping sections having notches in their lappingedge portions to form the stem opening, the collective formation of saidnotches providing the opening to receive the support member as thereinset forth, and one of said telescoping sections having a shoulderwhereby the watchcase surface around said opening is substantially allin a single plane whereby the flange of the support member has itsbearing against the exterior of the'case as therein set forth.

' LEOPOLD HOFFER.

